1. Field of the Invention
The present invention relates to an information processing apparatus connected to a network via a network interface device and capable of communicating with a server on the network.
2. Description of the Related Art
In an information processing apparatus, such as a multifunction peripheral or a printer, various techniques for reducing power consumption have been introduced hitherto. Among them, a technique called a deep sleep is to put the information processing apparatus into a sleep state by stopping supplying power to respective areas except for a random-access memory (RAM) and a network interface card (hereinafter, NIC) of the information processing apparatus and an operation unit of the information processing apparatus. Accordingly, it becomes possible to reduce power consumption to a very low value when the information processing apparatus is in the deep sleep state.
In such a deep sleep technology for enabling the information processing apparatus to operate with a very low electricity, when the information processing apparatus is in the deep sleep state, the passage of electric current through drums and fixing devices in a printer unit and a central processing unit (CPU) and a hard disk drive (HDD) in a controller unit is stopped. At this time, the information processing apparatus cannot execute main functions such as printing and image processing that the information processing apparatus has.
The information processing apparatus has a condition for shifting from the deep sleep state to a normal state (standby state). If the information processing apparatus satisfies the condition, it starts supply of electric power to the areas to which the supply of electric power has been stopped, and returns to a state (standby state) that renders the main functions of the information processing apparatus to be usable.
Generally, the return condition includes two cases: (1) a button in the operation unit of the information processing apparatus is pressed, and (2) the NIC of the information processing apparatus receives a particular network packet that meets the return condition. Thus, even when the information processing apparatus is in the deep sleep state, electric power is supplied to the operation unit and the NIC, and a sensor monitors whether the button is pressed and whether the network packet is received.
A particular network packet that meets the return condition described above includes generally 1) a packet forwarded to the information processing apparatus itself (a packet of which destination Media Access Control (MAC) address is the information processing apparatus itself), 2) a sleep return packet, and 3) a broadcast packet of particular protocol. The sleep return packet 2) refers to a packet having a particular packet pattern for causing the information processing apparatus to return from the deep sleep state. The broadcast packet of particular protocol 3), or a multicast packet, refers to a packet for another node on the network to search for an information processing apparatus on the network. The information processing apparatus is configured such that, if a packet received by the NIC is any one of these packets, the information processing apparatus returns from the deep sleep state to the standby state.
Further, some information processing apparatuses in recent years have a function called a proxy response that enables them to respond to a given network packet even when they are in the deep sleep state. As described above, since the CPU of the information processing apparatus is also stopped in the deep sleep state, normally the information processing apparatus cannot respond to a packet that it has received. Therefore, when the information processing apparatus receives a packet that a node on the LAN has forwarded to the information processing apparatus, the above-described return condition is satisfied, so that the information processing apparatus may return without exception from the deep sleep state. Accordingly, in an environment where there are such nodes that perform frequently communication to the information processing apparatus, or in such an environment as where many nodes exist, even though frequency of the communication is less, the information processing apparatus may frequently return from the deep sleep. Consequently, the deep sleep state cannot continue for long durations, and as a result, it is difficult to reduce power consumption to a lower level.
A technology to solve such an issue is a proxy response. The proxy response is to provide the NIC with a function of responding to a particular packet. With this technology, it becomes possible for the information processing apparatus to respond to a packet (reply to a packet) having a particular data pattern, out of network packets that the information processing apparatus has received from the LAN, without returning from the deep sleep mode. Thus, it has become possible to cause the deep sleep state to continue as long as possible and to reduce power consumption of the information processing apparatus to a lower level. Regarding the proxy response technology, for example, Japanese Patent Application Laid-Open No. 2006-259906 discusses an image processing apparatus provided with a CPU 1 that performs normal processing and a CPU 2 that operates in the power-saving state. Then a technology in which the CPU 2 responds to a received packet in the power-saving state is discussed therein. In the conventional proxy response technology, the NIC can only perform response processing to the received network packet. That is, the NIC only performs passive processing for responding to the received packet.
Nowadays, however, various network environments are built, and thus the information processing apparatus used in these network environments can perform processing for adapting to each of the network environments. There is a case where, even if the information processing apparatus is in the deep sleep state, it may be needed sometimes to actively transmit a network packet from the information processing apparatus.
For example, in a LAN environment in which computers equipped with Microsoft's Windows (registered trademark) operating systems are introduced, a name management server called a master browse server (hereinafter, called an MBS) exists. The MBS is not explicitly set up by administrators or users of the LAN but is determined by nodes on the LAN performing negotiations with one another. Therefore, an information processing apparatus participating in the network environment searches for the MBS at a given interval and then performs processing of registering the computer name (Network Basic Input Output System (NetBIOS) name) of the information processing apparatus itself on the found MBS at a given interval. This is because information saved in the MBS will be deleted at a given elapse of time, so that each node on the LAN including the information processing apparatus is to perform re-registration before information of the information processing apparatus itself is deleted. The NetBIOS name is information used during transmission and reception of files among the network nodes using a Server Message Block (SMB).
In this process, update time information such as time or interval when or at which the MBS deletes information varies according to types of network environments or operating systems. Then, a time interval is set for the information processing apparatus at which information of the information processing apparatus itself is registered on the MBS. Registration processing on the MBS in accordance with the setting is processed by the main CPU of the information processing apparatus. However, if the information processing apparatus is put into the above-described deep sleep state, the main CPU will be eventually stopped as described above. Consequently, there may be an issue that the information processing apparatus cannot know the time interval at which to register its own information on the MBS, thus becoming unable to execute any registration processing.
As another example, a device that supports NetBIOS and Transmission Control Protocol/Internet Protocol (TCP/IP), if a WINS server exists on the LAN, performs processing of registering a NetBIOS name and an Internet Protocol (IP) address of the information processing apparatus itself on the WINS server at a given interval. The WINS server (Windows (registered trademark) Internet Name Service server) is a server for managing the NetBIOS name and the IP address in a pair of each node on the network. The WINS server is installed by users such as administrators in the LAN environment. Hence, the information processing apparatus is provided with a registration unit for designating the WINS server. More specifically, the information processing apparatus includes the registration unit for registering the IP address of the WINS server. The information processing apparatus performs processing of registering a pair of the NetBIOS name and the IP address of the information processing apparatus itself in the registered address. When the registration is performed, the next registration time is designated from the WINS server to the information processing apparatus. When the designated registration time has been reached, the information processing apparatus performs again processing of registering a pair of the NetBIOS name and the IP address of the information processing apparatus itself on the WINS server. The series of registration processing is processed by the main CPU of the information processing apparatus. However, when the information processing apparatus enters into the above-described deep sleep state, the main CPU will be eventually stopped as described above. Consequently, the information processing apparatus cannot know address information and the like of the WINS server, and thus becomes unable to execute any registration processing.